The only difference is the area (volume) the engine uses to make power. This volume is measured in Litres. A 7.3L engine uses 7.3 litres of volume in the clyinders to make the power it produces. So...
A gas engine ignites gasoline in the piston chamber with a spark from a spark plug. The expanding gas then pushes the piston out and the motor moves forward. A diesel engine uses diesel fuel,...